1. Field of the Invention
The invention relates to original document reading devices having an array of secondary electron multipliers. The invention is more particularly concerned with an inexpensive and relatively simple original document reading apparatus utilizing an optical-electric signal converter comprising a photocathode, an array of secondary electron multipliers, and anodes arranged in the vicinity of and in line with the respective secondary electron multiplier output sides for converting a one-dimensional optical image focused on the photocathod into a series of electric signals. The secondary electron multipliers in the array each has a size corresponding to the size of the unit of the optical image to be read. The anodes for each are connected through a wire lead to the source electrode of a field effect semiconductor (FES) switch so as to take signals from its drain electrode by the ON and OFF operation of its gate electrode to determine the position to be read.
2. Prior Art
Various kinds of devices have been proposed to read an original document or particularly to convert an optical image into a series of electric signals. These include image pickup tube, solid state image senser, and a combination of a photomultiplier and a laser scanning device. Such devices may conceivably be miniaturized for utilization as an original document reading apparatus, but this will generally result in a very expensive system and be difficult to bring to commercial practice.